Seventeen-year-old Mia Hall lives in a small town in Oregon with her Mom (Kat), Dad (Denny), and eight-year-old brother, Teddy. On one snowy morning, school is cancelled, leaving Mia and Teddy, as well as their father, an English teacher, with the day off. Mia’s Mom decides to take the day off from her job at a travel agency in order to spend the day with the rest of her family. They eat breakfast, and Mia’s Mom jokes that she’s surprised Mia isn’t spending the day practicing the cello. Mia is a talented cellist, and has recently auditioned for The Juilliard School in New York City, where she hopes to study the following year, after she graduates from high school. Everyone piles into the family car, and they start to drive. They plan to visit Willow and Henry, family friends who have a baby daughter, and to have dinner with Dad’s parents, Gran and Gramps, who live nearby.
Mia falls asleep while her parents drive, and suddenly wakes up to find the car “eviscerated.” The car has been totaled by a pickup truck, due to the snow on the roads, which is unusual for their part of Oregon. Mia finds her mother and father dead from the accident, and sees her own body, unconscious, still in the vehicle. She realizes she is having a kind of out-of-body experience: she cannot feel any pain, and appears to be able to move around as she pleases, though no one can see her. An ambulance soon arrives. Mia’s parents are declared dead on arrival, and she is taken to a nearby hospital, where she is then airlifted to a hospital in Portland.
In Portland, Mia undergoes an operation to treat her extensive injuries. After the surgery, she is brought to the intensive care unit, where her body is stable, though in a coma. Though her grandparents are allowed to visit her, the head nurse does not allow Adam, her boyfriend, and Kim, her best friend, to visit because they are not relatives. Adam, who is a guitarist in a popular local rock band called Shooting Star, concocts a scheme to have Brooke Vega, the lead singer of an even more famous local band called Bikini, play an impromptu concert in the hospital to distract the nurses while Adam and Kim sneak into the ICU to see Mia. While the scheme doesn’t work, the family’s friend Willow, who is a nurse at another hospital, is able to use her connections to let Adam and Kim in to see Mia.
As Mia cannot speak to anyone to ask about Teddy, she had assumed that Willow had previously been busy taking care of Teddy back in their local hospital. When she sees Willow in Portland, however, she deduces that Teddy is no longer alive. This realization causes Mia’s physical body to go into cardiac arrest, and she is rushed into surgery again to fix a perforation in her abdomen.
Mia is brought back into the ICU after surgery, stable though still in a coma. Nurse Ramirez, a young nurse in the hospital, tells Mia’s grandparents that Mia is “running the show,” meaning that it is up to her whether or not she will emerge from the coma. Mia realizes that her emotions and decisions in her out-of-body experience directly connect to her physical body, and that it is up to her to decide whether she will live or die. If she chooses to live, she will have to cope with the grief of the loss of her parents, while if she decides to die and join her immediate family in death, she will forfeit her entire future with the cello, as well as her love of Gran, Gramps, Kim, and Adam.
Mia weighs the pros and cons of living and dying through a series of flashbacks, in which she recalls memorable moments with her family, such as Teddy’s birth, for which she was present, and the trajectory of her relationship with Adam. Though Mia and Adam love each other, they had recently experienced tension in their relationship: Adam, who is one year older than Mia, is still living in their Oregon town because his band, Shooting Star, has quickly been gaining popularity and he has the potential to succeed as a musician. Should Mia be accepted to Juilliard, and Adam choose to remain in Oregon, an entire country will separate them. Mia is unsure if their relationship will survive the distance.
Mia makes it through the night. Exhausted, she feels as if she is ready to go to sleep, which will likely lead to her death. Adam comes to see Mia, puts headphones on her ears, and plays her the cello music of Yo-Yo Ma. The music brings up emotions and memories for Mia, both from the past and the future. She summons the strength to decide to stay, and squeezes Adam’s hand, indicating that she has woken up from her coma, and has decided to live.